Are you getting this following error in Exchange Console or Shell?
Connecting to remote server ExchServer.company.com failed with the following error message : The WS-Management service cannot process the request. The system load quota of 1000 requests per 2 seconds has been exceeded. Send future requests at a slower rate or raise the system quota.
It means, IIS/PowerShell App Pool is over loaded.
I saw on other sites on more drastic solution like running IISReset on Admin privileged command prompt. That would affect entire Exchange client features.
Logon to the specfic Exchange server on the error message
Open IIS Management Console and navigate to IIS Application Pools
Restart PowerShell App Pools